Like many electronic components, capacitors generate heat under certain conditions, and this heat must be controlled and dissipated to avoid component and system damage. Capacitors in particular generate substantial heat when subjected to high ripple currents. When such currents must be tolerated, capacitors must be made robust, requiring them to be larger than would otherwise be desirable. Where miniaturization is particularly critical, designers face an unwelcome tradeoff between size and current handling capacity.
To reduce these disadvantages, heat generating components have been fitted with radiative heat sinks in contact with their external housing surfaces. Such heat sinks may also be in the form of a metal circuit substrate to which the components are mounted. A limitation of conventional heat sinks is that close thermal coupling is difficult. Adhesives used to maintain a large contact area must generally be electrically insulative, which limits their thermal conductivity. Conventional component housings also increase the thermal isolation of the hot conductors in the component and the heat sink. In addition, it is often desirable to provide capacitors with the maximum capacitance per unit volume, and current designs are limited in this respect.
The present invention overcomes the limitations of the prior art by providing an electrolytic capacitor with several conductive layer portions, including some anode layers and some cathode layers in alternating arrangement. A set of insulator layers is interleaved with the conductive layers, and the conductive and insulator layers are laminarly stacked with an anode layer being outermost on one surface. The stack is positioned adjacent a metal heat sink, with an outer insulator layer positioned between and closely contacting the stack and the heat sink. The cathode layers may be connected to the heat sink.